DockerCLI/cli
Sebastiaan van Stijn f28fc7f82f
cli: FlagErrorFunc: don't print long usage output for invalid flags
When trying to use an invalid flag, the CLI currently prints the a short
error message, instructions to use the `--help` flag to learn about the
correct usage, followed by the command's usage output.

While this is a common convention, and may have been a nice gesture when
docker was still young and only had a few commands and options ("you did
something wrong, but here's an overview of what you can use"), that's no
longer the case, and many commands have a _very_ long output.

The result of this is that the error message, which is the relevant
information in this case - "You mis-typed something" - is lost in the
output, and hard to find (sometimes even requiring scrolling back).

The output is also confusing, because it _looks_ like something ran
successfully (most of the output is not about the error!).

Even further; the suggested resolution (try `--help` to see the correct
options) is rather redundant, because running teh command with `--help`
produces _exactly_ the same output as was just showh, baring the error
message. As a fun fact, due to the usage output being printed, the
output even contains not one, but _two_ "call to actions";

- `See 'docker volume --help'.` (under the erro message)
- `Run 'docker volume COMMAND --help' for more information on a command.`
  (under the usage output)

In short; the output is too verbose, confusing, and doesn't provide
a good UX. Let's reduce the output produced so that the focus is on the
important information.

This patch:

- Changes the usage to the short-usage.
- Prefixes the error message with the binary / root-command name
  (usually `docker:`) to be consistent with `unknon command`, and helps
  to distinguish where the message originated from (the `docker` CLI in
  this case).
- Adds an empty line between the error-message and the "call to action"
  (`Run 'docker volume --help' ...` in the example below). This helps
  separating the error message ("unkown flag") from the call-to-action.

Before this patch:

    docker volume --no-such-flag
    unknown flag: --no-such-flag
    See 'docker volume --help'.

    Usage:  docker volume COMMAND

    Manage volumes

    Commands:
      create      Create a volume
      inspect     Display detailed information on one or more volumes
      ls          List volumes
      prune       Remove unused local volumes
      rm          Remove one or more volumes
      update      Update a volume (cluster volumes only)

    Run 'docker volume COMMAND --help' for more information on a command.

With this patch:

    docker volume --no-such-flag
    docker: unknown flag: --no-such-flag

    Usage:  docker volume COMMAND

    Run 'docker volume --help' for more information

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2024-07-17 13:22:31 +02:00
..
command Merge pull request #5234 from thaJeztah/nicer_missing_commands 2024-07-17 01:22:03 +02:00
compose vendor: github.com/docker/docker 1a1f3cff45ec (master, v27.0-dev) 2024-06-20 13:04:54 +02:00
config test spring-cleaning 2024-07-04 01:35:12 +02:00
connhelper Removed all mentions of "please" from docs and messages 2024-06-11 16:53:40 +02:00
context Update go:build comments to go1.21 2024-06-18 12:17:13 +02:00
debug command: include default otel error handler for the cli 2024-04-03 12:01:28 -05:00
flags cli: move "config" flag to cli/flags/ClientOptions.InstallFlags() 2023-06-28 16:04:09 +02:00
hints login: Add message about using PATs 2023-08-03 10:35:04 +02:00
manifest linting: fmt.Sprintf can be replaced with string concatenation (perfsprint) 2024-06-10 21:19:32 +02:00
registry/client use local ConvertToHostname() implementation 2024-06-14 00:25:21 +02:00
streams cli/streams: minor refactoring and docs touch-ups 2023-04-03 11:27:26 +02:00
trust chore: remove deprecated DualStack field 2024-04-15 17:53:35 +08:00
version Move versioning variables to a separate package. 2019-01-29 11:26:40 +00:00
winresources Use goversioninfo to create Windows Version Info 2021-10-11 16:54:22 +02:00
cobra.go cli: FlagErrorFunc: don't print long usage output for invalid flags 2024-07-17 13:22:31 +02:00
cobra_test.go cli: use custom annotation for aliases 2022-06-28 17:32:09 +02:00
error.go cli: make cli.StatusError slightly prettier 2024-07-04 22:08:18 +02:00
required.go cli: improve argument validation output 2024-07-05 03:35:14 +02:00
required_test.go cli: improve argument validation output 2024-07-05 03:35:14 +02:00